To maintain an ecological balance within an aquarium, it is necessary to clean the aquarium water. Cleaning is often accomplished by pumping water from the aquarium to a filter housing. In the filter housing, the water is mechanically filtered through a filter element and then returned to the aquarium. Some filter elements further provide chemical filtration to filter chemicals and organics that can build up in the aquarium water.
In one chemical filtration arrangement, charcoal pellets are deposited into a central volume of a filter element or bag. The charcoal pellets settle at the bottom of the bag during filtration use. A significant portion of water can bypass the settled charcoal pellets and therefore not obtain the benefit of the chemical filtration.
In another chemical filtration arrangement, carbon is bonded to a carbon carrier or carbon layer, which is in turn secured to the filter element. The bonding process in the manufacture of the carbon carrier, however, often occludes or obstructs the surface area of the carbon, reducing the carbon's capacity to capture organics in the water.
In yet other chemical filtration arrangements, carbon is distributed over portions of the face area of a filter element by use of shelf-like features formed in injection molded shells, or by the use of pockets sewn into the filter element. The shelf-like features and pockets compartmentalize the carbon so that the carbon is distributed across the face area of the filter element. Manufacture of such shell structures and pocketed filter elements is expensive and adds significant costs to the making of filter elements.
In general, filter devices and arrangements used for filtering aquarium water can be improved.